KR20150145182A

KR20150145182A - Photocurable composition for transparent adhesive sheet and transparent adhesive sheet

Info

Publication number: KR20150145182A
Application number: KR1020150081842A
Authority: KR
Inventors: 겐이치 나카니시; 다이고 이토; 가즈히로 사사키; 유타 다케우치
Original assignee: 쇼와 덴코 가부시키가이샤
Priority date: 2014-06-18
Filing date: 2015-06-10
Publication date: 2015-12-29
Also published as: TWI601798B; TW201610062A; KR101747522B1; JP6634621B2; JP2016020477A

Abstract

The present invention relates to a photo-curable composition for a transparent adhesive sheet and a transparent adhesive sheet. The photo-curable composition for the transparent adhesive sheet comprises: (A) polyurethane; (B) (meth)acrylic acid ester having a hydroxy group; (C) (meth) acrylic acid ester containing an aromatic group; (D) a polymerizable monomer besides the (A) to (C) elements; (E) and a photopolymerization initiator. In addition, provided is a cured product in which an acid value is 0 to 5 mgKOH/g and a refractive index is 1.50 to 1.60.

Description

TECHNICAL FIELD [0001] The present invention relates to a photocurable composition for a transparent adhesive sheet and a transparent adhesive sheet for a transparent adhesive sheet,

The present invention relates to a photo-curable composition for a transparent adhesive sheet, a transparent adhesive sheet formed by curing the photo-curable composition, and a transparent conductive film laminate using the transparent adhesive sheet for bonding a transparent conductive film. The laminate can be used for a touch panel, and is useful for use in an image display device.

The present application claims priority based on Japanese Patent Application No. 2014-125549 filed in Japan on June 18, 2014, the content of which is hereby incorporated by reference.

2. Description of the Related Art Recently, touch panels widely used in the fields of mobile phones, game devices, and the like include a transparent substrate such as glass having a transparent conductive film such as ITO (indium tin oxide) or silver nanowire as a surface layer, A laminate obtained by bonding an optical member such as a display device such as a liquid crystal display using a transparent pressure sensitive adhesive sheet.

Most of the touch panels have a capacitance type touch panel that detects an input portion by static electricity from the human body at the time of input. In a capacitive touch panel, the conductive layer surface of the transparent conductive film is fixed so as to be in contact with the surface of the adhesive sheet. The pressure sensitive adhesive used for this purpose generally contains an acid component for the purpose of improving the adhesiveness. However, when such a pressure sensitive adhesive is used, when the pressure sensitive adhesive sheet touches the conductive layer surface of the transparent conductive film, There is a problem in that the conductive function is deteriorated. As a result, a high corrosion resistance of the metal is required for the pressure-sensitive adhesive sheet for fixing a transparent conductive film.

As a pressure-sensitive adhesive sheet having metal corrosion-preventive properties, a pressure-sensitive adhesive sheet (for example, Patent Document 1) containing a metal corrosion inhibitor has been proposed. Further, there has been proposed a pressure-sensitive adhesive sheet (for example, Patent Document 2) in which the corrosiveness to the transparent conductive film is reduced by containing a specific amount of a nitrogen atom-containing component in the acid component of the pressure-sensitive adhesive sheet.

In addition, an acrylic pressure-sensitive adhesive sheet using an acrylic copolymer as a base polymer is used as a pressure-sensitive adhesive sheet used when bonding various optical members, liquid crystal panels, various light sources, and diffusion plates with good transparency and weather resistance. However, in the acrylic pressure-sensitive adhesive sheet, the index of refraction of the optical member is 1.51 or more, for example, and 1.54 or more for polycarbonate, while the refractive index of the optical member is generally about 1.47, while the refractive index of the acrylic copolymer is low. There is a large difference in refractive index between the sheet and the optical member. Therefore, when an acrylic pressure sensitive adhesive sheet is used as the pressure sensitive adhesive sheet for optical members, a refractive index difference occurs at the interface between the optical member and the acrylic pressure sensitive adhesive, which hinders effective use of light.

For the purpose of solving such a problem, attempts have been made to produce an acrylic pressure sensitive adhesive sheet having a high refractive index. For example, Patent Document 3 proposes a method of improving the refractive index of the acrylic pressure-sensitive adhesive sheet by optimizing the constitution of the pressure-sensitive adhesive composition and the high-refractive-index tackifier.

Japanese Patent Application Laid-Open No. 2006-45315 Japanese Patent Application Laid-Open No. 2010-144002 Japanese Patent Application Laid-Open No. 2006-342258

However, in the pressure-sensitive adhesive sheet containing the metal corrosion inhibitor described in Patent Document 1, the metal corrosion inhibitor tends to cause discoloration and has a problem of deteriorating optical characteristics. The pressure sensitive adhesive sheet containing a specific amount of the nitrogen atom-containing component described in Patent Document 2 has a problem that the increase in electric resistance value of ITO can not be sufficiently suppressed due to the acid component contained therein.

Further, in the method described in Patent Document 3, although the refractive index can be satisfied, there is a problem that a carboxyl group, which is an acid component, must be introduced in order to increase the adhesive strength.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and it is an object of the present invention to provide a transparent adhesive sheet, which is excellent in transparency and adhesive strength, A transparent adhesive sheet obtained by curing a curable composition, a photocurable composition for a transparent adhesive sheet, and a transparent conductive film laminate obtained by bonding the transparent adhesive sheet to a conductive layer surface of a transparent conductive film. Further, there is provided a touch panel using the above-mentioned transparent conductive film laminate, and an image display device provided with the touch panel.

The present invention is based on the following [1] to [10].

(1) a polyurethane (A) having a (meth) acryloyl group at the terminal and having a weight average molecular weight of 10,000 to 300,000, a (meth) acrylic ester (B) having a hydroxy group, ) Acrylic ester (C), a polymerizable monomer (D) other than the above components (A) to (C) and a photopolymerization initiator (E) and having an acid value of 0 to 5 mgKOH / g Photocurable composition.

[Chemical Formula (1)

CH ₂ ═CR ¹ -CO-OR ² - (O) _n -A (1)

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is an alkylene group having 1 to 6 carbon atoms, A is a group having an aromatic ring, and n is 0 or 1.)

[2] The photocurable composition for a transparent pressure-sensitive adhesive sheet according to [1], wherein the polyurethane (A) is a polyurethane having a (meth) acryloyl group bonded to the end of a polyoxyalkylene chain via a urethane bond.

[3] The ink composition according to any one of [1] to [3], wherein the polyurethane (A) is contained in an amount of 10 to 40% by weight, the (meth) acrylic acid ester (B) (E) relative to 100 parts by mass of the polymerizable monomer (D) other than the components (A) to (C) in an amount of 40 to 70% by mass, Is in the range of 0.05 to 5 parts by mass based on the total amount of the thermosetting resin composition.

[4] The photocurable composition for a transparent pressure-sensitive adhesive sheet according to any one of [1] to [3], wherein A in the formula (1) is a group having one or two aromatic rings.

[5] The positive resist composition according to any one of [1] to [4], wherein the (meth) acrylic acid ester (B) having a hydroxy group is a hydroxyalkyl (meth) acrylate and the alkyl moiety has 2 to 10 carbon atoms. A photocurable composition for a pressure-sensitive adhesive sheet.

[6] The polyurethane resin composition according to any one of [1] to [5], wherein the polyurethane (A) is a polyurethane in which an acryloyl group is bonded through a urethane bond to the end of a polyoxyalkylene chain having 3 carbon atoms in the repeating unit, ) Is hydroxyethyl acrylate, and the (meth) acrylic acid ester (C) represented by the above formula (1) is at least one selected from the group consisting of m-phenoxybenzyl acrylate, 2- (1-naphthyloxy) ethylhexyl acrylate, and benzyl acrylate, and the polymerizable monomer (D) other than the components (A) to (C) is at least one selected from the group consisting of 2-ethylhexyl acrylate and / Or isostearyl acrylate, wherein the photo-curable composition for a transparent pressure-sensitive adhesive sheet according to any one of [1] to [5]

(7) A polyester resin composition comprising 9 to 41% by mass of the polyurethane (A), 1 to 16% by mass of a (meth) acrylic acid ester (B) having a hydroxy group, a (meth) acrylic acid ester 40 to 71% by mass in the case of m-phenoxybenzyl acrylate, 40 to 55% by mass in the case of 2- (1-naphthyloxy) ethyl acrylate, 2- (o-phenylphenoxy) Phenoxybenzyl acrylate and benzyl acrylate, it is preferable that the amount of m-phenoxybenzyl acrylate is 39 to 70 mass% and the amount of benzyl acrylate is 1.0 to 10 mass% (E) in an amount of 0.5 to 3 parts by mass relative to 100 parts by mass of the polymerizable monomer (D) other than the components (A) to (C) in an amount of 8 to 28% by mass and the components (A) The photo-curable composition for a transparent pressure-sensitive adhesive sheet according to [6].

[8] The photocurable composition for a transparent pressure-sensitive adhesive sheet according to [1], which is provided with a cured product having a refractive index of 1.50 to 1.60.

[9] A transparent pressure-sensitive adhesive sheet having a refractive index of 1.50 to 1.60 obtained by curing the photocurable composition for a transparent pressure-sensitive adhesive sheet according to any one of [1] to [8].

[10] The pressure-sensitive adhesive sheet for fixing a transparent conductive film according to [9], which is used for bonding a transparent conductive film.

[11] The transparent conductive film laminate according to [10], wherein the pressure-sensitive adhesive sheet for fixing a transparent conductive film is bonded to the surface of the conductive layer of the transparent conductive film.

[12] A touch panel having the transparent conductive film laminate according to [11].

[13] An image display apparatus comprising the touch panel according to [12].

According to the present invention, it is possible to provide a photo-curing composition for a transparent pressure-sensitive adhesive sheet, which is excellent in tackiness and transparency and which can obtain a transparent pressure-sensitive adhesive sheet having a high refractive index. Further, since the acid value of the composition is at most 5 mgKOH / g even when the acid value of the composition is maximum, corrosion of the transparent conductive film due to the acid component can be suppressed when the transparent adhesive sheet is produced and attached to the conductive layer surface of the transparent conductive film. Furthermore, by including a (meth) acrylic acid ester having a hydroxy group, a high cohesive force and adhesion to a substrate can be obtained.

Further, since the transparent pressure sensitive adhesive sheet of the present invention is excellent in high refractive index, it is possible to obtain a touch panel having excellent visibility in application to a transparent resin substrate.

Next, embodiments for carrying out the present invention will be described. Further, in the specification and claims of the present application, the term " (meth) acryloyl group &

A group represented by the formula CH ₂ = CH-CO- or

Means a group represented by the formula CH ₂ C (CH ₃ ) -CO-,

The isocyanate group,

Means a group represented by the formula: -N = C = O.

&Lt; Photocurable composition for transparent adhesive sheet >

The photocurable composition for a transparent pressure-sensitive adhesive sheet of the present invention comprises a polyurethane (A) having a (meth) acryloyl group at the terminal and a weight average molecular weight of 10,000 to 300,000, a (meth) acrylic acid ester (Meth) acrylate ester (C) represented by the general formula (1), a polymerizable monomer (D) other than the components (A) to (C) and a photopolymerization initiator (E) and having an acid value of 0 to 5 mg KOH / g . The photocurable composition for a transparent pressure-sensitive adhesive sheet of the present invention gives a cured product having a refractive index of 1.50 to 1.60.

[Chemical Formula (1)

CH ₂ ═CR ¹ -CO-OR ² - (O) _n -A (1)

&Lt; Polyurethane (A) >

The polyurethane (A) used in the present invention is a polyurethane having a (meth) acryloyl group at the terminal and a weight average molecular weight of 10,000 to 300,000. The polyurethane (A) may be a polyurethane having a (meth) acryloyl group bonded to the end of the polyoxyalkylene chain via a urethane bond. The polyurethane (A) may be a polyurethane having an acryloyl group bonded to the end of a polyoxyalkylene chain having 3 carbon atoms in the repeating unit through an urethane bond.

The polyol component used in the production of the polyurethane (A) is not particularly limited, but a polyoxyalkylene polyol is preferable. As the polyoxyalkylene polyol, a polyoxyalkylene polyol having an alkylene chain having 2 to 4 carbon atoms is preferable. Preferable polyoxyalkylene polyols include, for example, polyoxyethylenetylene polyol, polyoxypropylene polyol, polyoxybutylene polyol, and polytetramethylene ether glycol. These polyoxyalkylene polyols are obtained by subjecting alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to the addition polymerization. As the polyoxyalkylene polyols used in the present invention, one kind of alkylene oxide or the like is used A copolymer obtained by subjecting not only an addition polymer but also two or more kinds of alkylene oxides to addition copolymerization may be used. In addition, two or more polyoxyalkylene polyols may be blended and used. Among them, polyoxyalkylene diol is preferable, and polyoxyethylene diol and polyoxypropylene polyol are more preferable.

The number average molecular weight of the polyoxyalkylene polyol is usually 500 to 5,000, preferably 800 to 4,000. When the number average molecular weight of the polyoxyalkylene polyol is 500 to 5,000, the adhesive strength when the transparent pressure sensitive adhesive sheet is produced by producing the polyurethane (A) is improved and the cohesive force of the transparent pressure sensitive adhesive sheet is maintained do.

The polyisocyanate used in the production of the polyurethane (A) of the present invention is not particularly limited, and examples thereof include tolylene diisocyanate and hydrogenated products thereof, xylylene isocyanate and hydrogenated products thereof, diphenylmethane diisocyanate and hydrogenated products thereof, 5-naphthylene diisocyanate and its hydrogenated product, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxsilylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexyldiisocyanate, 1,3-bis (Isocyanatomethyl) cyclohexane, and norbornadiisocyanate. These may be used in combination of two or more. Among them, a hydrogenated product of isophorone diisocyanate or diphenylmethane diisocyanate is preferable from the viewpoint of light resistance and reactivity control.

The polyurethane (A) used in the present invention can be produced by a conventional method using a polyol and a polyisocyanate.

A preferred first synthesis method is as follows. First, the polyol and the polyisocyanate are reacted in such a ratio that the amount of the isocyanate group (the number of isocyanate groups) becomes greater than the amount of the hydroxy group (the number of the hydroxy groups), thereby synthesizing a polyurethane having an isocyanate group. At this time, it is possible to adjust the molecular weight by adjusting the ratio of the amount of isocyanate groups to the amount of hydroxyl groups. Specifically, the smaller the ratio of the isocyanate group amount to the hydroxyl group amount is, the larger the molecular weight of the polyurethane having isocyanate group becomes, and the larger the ratio of the isocyanate group amount to the hydroxy group amount is, the smaller the molecular weight of the polyurethane having isocyanate group becomes.

Then, the polyurethane (A) is synthesized by reacting a polyurethane having an isocyanate group with a compound having a hydroxy group and a (meth) acryloyl group.

Examples of the compound having a hydroxyl group and a (meth) acryloyl group include, but not limited to, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl Hydroxyalkyl (meth) acrylate; (Meth) acrylate, 1,3-butanediol mono (meth) acrylate, 1,4-butanediol mono (meth) acrylate, 1,6-hexanediol mono Monol having a (meth) acryloyl group derived from various polyols, and the like. These may be used in combination of two or more. Among them, 2-hydroxyethyl (meth) acrylate is preferable in view of reactivity with an isocyanate group and photocurability.

At this time, the amount of the (meth) acryloyl group introduced can be adjusted by reacting one alkyl alcohol with a polyurethane having an isocyanate group in the hydroxyl group. Examples of the alkyl alcohol include, but are not limited to, linear, branched, and alicyclic alkyl alcohols. These alkyl alcohols may be used in combination of two or more kinds.

The amount of the (meth) acryloyl group introduced is usually 50 to 100 mol%, preferably 80 to 100 mol%, and more preferably 100 mol% with respect to the isocyanate group. When the amount of the (meth) acryloyl group introduced is less than 50 mol% with respect to the isocyanate group, the cohesive force of the transparent pressure sensitive adhesive sheet may be lowered.

As a preferable second synthesis method of the polyurethane (A), a polyurethane having a hydroxyl group is synthesized by first reacting a polyol and a polyisocyanate at a ratio in which the amount of the hydroxy group is larger than the amount of the isocyanate group. Then, a polyurethane (A) is synthesized by reacting a polyurethane having a hydroxy group with a compound having an isocyanate group such as 2-acryloyloxyethyl isocyanate and a (meth) acryloyl group.

In the synthesis of the polyurethane (A), the reaction between the hydroxyl group and the isocyanate group is carried out in the presence of an isocyanate group in the presence of an inert organic solvent such as dibutyltin dilaurate, dibutyltin diethylhexoate and dioctyltin dilaurate Is generally carried out at 30 to 100 DEG C for about 1 to 5 hours by using an urethane-forming catalyst. The amount of the urethanation catalyst used is generally 50 to 500 mass ppm relative to the total mass of the reaction product.

The weight average molecular weight of the polyurethane (A) used in the present invention is 10,000 to 300,000, preferably 20,000 to 200,000, and more preferably 30,000 to 100,000. If the weight average molecular weight of the polyurethane (A) is less than 10,000, the adhesive strength of the transparent pressure sensitive adhesive sheet is lowered. On the contrary, if the weight average molecular weight exceeds 300,000, handling becomes difficult and workability is lowered.

The weight average molecular weight is a molecular weight in terms of polystyrene measured by gel permeation chromatography using Shodex (registered trademark) GPC-101 (manufactured by Showa Denko K.K.).

The content of the polyurethane (A) in the components (A) to (D) of the photocurable composition for a transparent pressure-sensitive adhesive sheet is suitably selected, but is preferably from 10 to 40 mass%, more preferably from 15 to 35 mass% , More preferably from 20 to 30 mass%. When the content of the polyurethane (A) is 10 to 40% by mass, the cohesive force and the adhesive force when used as the transparent pressure-sensitive adhesive sheet are good.

<(Meth) acrylic acid ester (B) having a hydroxy group>

The (meth) acrylic acid ester (B) having a hydroxyl group used in the present invention preferably has no carboxyl group (-COOH) in order to lower the acid value to a predetermined value or lower, and hydroxyalkyl (meth) acrylate Can be mentioned as a preferable example.

Specific examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (Meth) acrylate, 1,4-butanediol (meth) acrylate, 1,6-hexanediol (meth) acrylate and 3-methylpentanediol (meth) acrylate, Two or more species can be used in combination. The number of carbon atoms of the alkyl group of the hydroxyalkyl (meth) acrylate is usually 2 to 10, preferably 2 to 6, and more preferably 2 to 4. In particular, 2-hydroxyethyl (meth) acrylate is most preferable from the viewpoint of the adhesive strength of the resulting transparent pressure-sensitive adhesive sheet.

The content of the (meth) acrylic acid ester (B) having a hydroxy group in the components (A) to (D) of the photocurable composition for a transparent pressure-sensitive adhesive sheet is usually preferably from 2 to 10 mass%, more preferably from 3 to 9 By mass, and most preferably from 4 to 8% by mass. The transparent pressure-sensitive adhesive sheet obtained in the content of the (meth) acrylic acid ester (B) having a hydroxy group in the components (A) to (D) of the photocurable composition for a transparent pressure-sensitive adhesive sheet in an amount of 2 to 10 mass% .

<(Meth) acrylic acid ester (C)>

The (meth) acrylic acid ester (C) used in the present invention is a compound represented by the following formula (1).

[Chemical Formula (1)

CH ₂ ═CR ¹ -CO-OR ² - (O) _n -A (1)

In the formula, R ¹ represents a hydrogen atom or a methyl group.

In the formula, R ² represents a linear or branched alkylene group having 1 to 6 carbon atoms. R ² is preferably a linear or branched alkylene group having 1 to 3 carbon atoms, more preferably a linear alkylene group having 1 to 3 carbon atoms. Specific examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group and a hexylene group, and preferably a methylene group or an ethylene group.

Wherein n is 0 or 1.

In the formulas, A is a group having an aromatic ring, preferably an aromatic group having 6 to 18 carbon atoms or a group having 7 to 24 carbon atoms having an alkyl group or oxyalkyl group and an aromatic group, more preferably an aromatic group having 6 to 14 carbon atoms Or a group of 7 to 20 carbon atoms having an aromatic group and an alkyl or oxyalkyl group. As A, a group having one or two aromatic rings is preferable, and a group having a benzene ring or a naphthalene ring is more preferable. Specific examples thereof include a biphenyl group, a naphthyl group, and a phenoxyphenyl group.

Specific examples of the (meth) acrylic ester (C) include o-phenoxybenzyl (meth) acrylate, m-phenoxybenzyl (meth) acrylate, p-phenoxybenzyl (meth) Ethyl (meth) acrylate, 2- (1-naphthyloxy) ethyl (meth) acrylate, benzyl acrylate and the like. The use of these exemplified (meth) acrylic acid esters (C) provides excellent transparency, adhesive strength, and a high refractive index to a transparent pressure-sensitive adhesive sheet because of its excellent compatibility with polyurethane (A).

The content of the (meth) acrylic acid ester (C) in the components (A) to (D) of the photocurable composition for a transparent pressure-sensitive adhesive sheet is preferably from 40 to 70 mass%, more preferably from 45 to 65 mass% More preferably 50 to 60% by mass. When the content of the (meth) acrylic acid ester (C) in the components (A) to (D) of the photocurable composition for a transparent pressure sensitive adhesive sheet is 40 mass% or more, the refractive index of the obtained transparent pressure sensitive adhesive sheet can be kept high, When the content of the (meth) acrylic acid ester (C) in the light-curable composition for use is 70% by mass or less, the adhesive force of the resulting transparent pressure-sensitive adhesive sheet can be sufficiently secured.

In the photocurable composition for a transparent pressure-sensitive adhesive sheet of the present invention, a polymerizable monomer (D) other than the components (A) to (C) may also be used. However, in order to reduce the acid value to a predetermined value or less, it is preferable that the polymerizable monomer does not contain a carboxyl group. The polymerizable monomer (D) is not particularly limited and may be either monofunctional or polyfunctional, provided that it has a functional group capable of polymerizing a vinyl group, a (meth) acryloyl group and the like. The polymerizable monomers may be used alone or in combination of two or more. The term monofunctional or polyfunctional functional group as used herein refers to a functional group involved in polymerization such as vinyl group and (meth) acryloyl group.

Specific examples thereof include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, (Meth) acrylate, lauryl (meth) acrylate, isodecyl (meth) acrylate, n-hexyl (meth) acrylate, stearyl Alkyl (meth) acrylates such as (meth) acrylate;

Acrylate, norbornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, norbornyl Cyclic alkyl (meth) acrylates such as ethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate and tricyclodecane dimethylol di (meth) acrylate;

(Meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, 2-methoxyethoxyethyl (meth) acrylate, 2-ethoxyethoxyethyl Alkoxyalkyl (meth) acrylates such as acrylate;

Alkoxy (poly) alkylene glycol (meth) acrylates such as methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate and methoxydipropylene glycol (meth) acrylate; Fluorinated alkyl (meth) acrylates such as octafluoropentyl (meth) acrylate;

Dialkylaminoalkyl (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate and N, N-diethylaminoethyl (meth) acrylate;

Acrylates such as polyethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di Di (meth) acrylate di (meth) acrylate, 1,3-bis (hydroxyethyl) -5,5-dimethylhydantoin (Meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4-butanediol di Acrylate such as 1,6-hexanediol di (meth) acrylate, diacryloxyethyl phosphate, dipentaerythritol trihydroxy (meth) acrylate, pentaerythritol tetra Polyfunctional (meth) acrylate;

Acrylamide derivatives such as acrylamide, dimethylacrylamide, diethylacrylamide and (meth) acryloylmorpholine;

(Meth) acrylate containing an epoxy group such as glycidyl (meth) acrylate.

The content of the polymerizable monomer (D) in the components (A) to (D) of the photocurable resin composition for a transparent pressure-sensitive adhesive sheet is preferably 8 to 30% by mass, more preferably 10 to 25% And preferably 15 to 20% by mass.

&Lt; Photopolymerization initiator (E) >

Examples of the photopolymerization initiator (E) used in the present invention include, but are not limited to, benzophenone, benzyl, benzoin, omega -bromoacetophenone, chloroacetone, acetophenone, 2,2-diethoxyacetophenone, Dimethylacetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone Butyl ether, benzylmethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-benzoin methyl ether, benzoin isobutyl ether, benzoin- Methylbenzoylformate, 2,2-diethoxyacetophenone, 4-N, N ', N'- - carbonyl photopolymerization initiators such as dimethyl acetophenone and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one;

Sulfide-based photopolymerization initiators such as diphenyl disulfide, dibenzyl disulfide, tetraethyl thiuram disulfide, and tetramethyl ammonium monosulfide;

Acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide;

Quinone-based photopolymerization initiators such as benzoquinone and anthraquinone;

Azo-based photopolymerization initiators such as azobisisobutylonitrile and 2,2'-azobispropane;

A sulfochloride-based photopolymerization initiator;

Thioxanthone photopolymerization initiators such as thioxanthone, 2-chlorothioxanthone and 2-methylthioxanthone;

And peroxide-based photopolymerization initiators such as benzoyl peroxide and di-t-butyl peroxide. These may be used alone, or two or more of them may be used in combination. Among them, 1-hydroxycyclohexyl phenyl ketone and / or 2,4,6-trimethylbenzoyldiphenylphosphine oxide are preferable from the viewpoint of solubility in the transparent pressure-sensitive adhesive sheet photo-curable composition.

The content of the photopolymerization initiator (E) is preferably from 0.05 to 5 mass parts per 100 mass parts of the components (A) to (D) in the photocurable composition for a transparent pressure-sensitive adhesive sheet from the viewpoints of the photocurability and the strength and tackiness balance of the obtained transparent pressure- More preferably 0.5 to 3 parts by mass. When the content of the photopolymerization initiator (E) is 0.05 parts by mass or more, sufficient photo-curing performance is obtained. When the content is 5 parts by mass or less, sufficient adhesion of the transparent pressure-sensitive adhesive sheet is obtained.

The acid value of the photocurable composition for a transparent pressure-sensitive adhesive sheet of the present invention is 0 to 5 mgKOH / g, preferably 0 to 0.5 mgKOH / g, and more preferably 0 to 0.1 mgKOH / g. When the acid value is higher than 5 mgKOH / g, it is difficult to suppress the corrosion of the conductive layer surface of the transparent conductive film. The acid value of the composition is a value measured in accordance with JIS K0070 and is measured as follows.

About 2 g of the sample is precisely weighed in a 100 ml Erlenmeyer flask with a precision balance, and 10 ml of a mixed solvent of ethanol / diethyl ether = 1/1 (weight ratio) is added and dissolved. Further, 1 to 3 drops of an ethanol solution of phenolphthalein is added as an indicator to the container, and the mixture is sufficiently stirred until the sample becomes uniform. This is titrated with a 0.1 N potassium hydroxide-ethanol solution, and when the light pink of the indicator continues for 30 seconds, it is used as the end point of neutralization. From the result, the value obtained by using the following formula (2) is the acid value of the composition.

Acid value (mgKOH / g) = [B x f x 5.661] / S (2)

B, f and S in the calculation formula (2) are as follows.

B: Amount of the 0.1 N potassium hydroxide-ethanol solution (ml)

f: Factor of 0.1N potassium hydroxide-ethanol solution (correction of shaking due to reagent lot)

S: Weight of sample (g)

The refractive index of the cured product of the photocurable composition for a transparent pressure-sensitive adhesive sheet of the present invention is 1.50 to 1.60, preferably 1.52 to 1.60. Here, the refractive index refers to the refractive index in the light having a wavelength of 589 nm at 25 캜. When the refractive index is from 1.50 to 1.60, the refractive index difference from the optical member to be bonded becomes small, so that it can be favorably used as the optical member adhesive sheet.

In the photocurable composition for a transparent pressure-sensitive adhesive sheet of the present invention, a tackifier resin may be added within a range not lowering transparency, in order to improve the adhesive strength of the obtained transparent pressure-sensitive adhesive sheet, if necessary. Examples of the tackifier resin include rosin-based resins such as rosin and esters of rosin; Terpene resins such as diterpene polymers and? -Pinene-phenol copolymers; Petroleum resins such as aliphatic (C5) and aromatic (C9); Other examples include styrene resins, phenol resins, and xylene resins. It is preferable to add a styrene resin or the like to the transparent pressure-sensitive adhesive sheet in terms of transparency and refractive index. The amount of the tackifier resin to be added is in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the photocurable composition for a transparent pressure-sensitive adhesive sheet.

The photo-curable composition for a transparent pressure-sensitive adhesive sheet of the present invention may contain various known additives, as needed, within a range that does not impair transparency. Examples of additives include antistatic agents such as plasticizers, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, light stabilizers, ultraviolet absorbers, light stabilizers such as polymerization inhibitors and benzotriazole, phosphate esters and other flame retardants, Dye and the like.

Since the photocurable composition for a transparent pressure-sensitive adhesive sheet of the present invention contains a (meth) acrylic acid ester (B) having a hydroxy group and a (meth) acrylic acid ester (C) represented by the formula (1) Although it is possible to adjust the viscosity to a value which can be applied without the necessity, an organic solvent may be added for the purpose of adjusting the viscosity at the time of application. Examples of the organic solvent to be used include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, n-propanol and isopropanol. These organic solvents may be used alone or in combination of two or more.

The light-curable composition for a transparent pressure-sensitive adhesive sheet of the present embodiment has a low acid value, and the transparent pressure-sensitive adhesive sheet as a cured product thereof can suppress corrosion of the conductive surface when the transparent pressure-sensitive adhesive sheet is adhered to the conductive layer surface of the transparent conductive film, Respectively. This effect is obtained based on the synergistic effect of the components (A) to (D). Specifically, the polyurethane (A) having a specific weight average molecular weight contributes to improvement in adhesion while securing the transmittance of the transparent pressure-sensitive adhesive sheet. Further, the (meth) acrylic acid ester (B) having a hydroxy group improves the cohesion of the transparent adhesive sheet and the adhesion to the substrate, thereby contributing to the improvement of the adhesive strength of the transparent adhesive sheet. Further, the (meth) acrylic acid ester (C) represented by the formula (1) improves the refractive index of the pressure-sensitive adhesive sheet without impairing transparency. The polymerizable monomer (D) other than the components (A) to (C) contributes to the adjustment of the Tg of the transparent pressure-sensitive adhesive sheet and the improvement of the adhesiveness to the substrate.

&Lt; Transparent adhesive sheet >

The transparent pressure sensitive adhesive sheet of the present invention is suitably used as an optical pressure sensitive adhesive sheet obtained by curing the above-mentioned photocurable composition for a transparent pressure sensitive adhesive sheet and used for optical use. More specifically, the present invention relates to a transparent pressure-sensitive adhesive sheet for use in joining optical members (for joining optical members). The Tg of the cured product forming the transparent pressure sensitive adhesive sheet is preferably -10 to -60 캜, more preferably -20 to -50 캜. When the Tg of the cured product is not higher than -10 占 폚, the transparent pressure sensitive adhesive sheet maintains flexibility and is excellent in level absorbability, and the Tg of the cured product is -60 占 폚 or higher. The transparent pressure sensitive adhesive sheet may have a base material formed of a transparent resin sheet such as PET or a double side pressure sensitive adhesive sheet having no base material but only a pressure sensitive adhesive layer. The pressure-sensitive adhesive layer may include a single layer, or a plurality of layers may be laminated. An example of a plurality of pressure-sensitive adhesive layers laminated is, for example, a transparent pressure-sensitive adhesive sheet having a three-layer structure and a balance between the cohesive force and adhesive force by changing the compositions of the layers on both sides and the center layer.

The optical member to be bonded is not particularly limited as long as it is a member having optical properties, and examples thereof include an image display device, a member constituting a touch panel or a member used in the device. More specifically, for example, a polarizing plate, a retardation film, an optical compensation film, a luminance enhancement film, a light guide plate, a reflective film, an antireflection film, a transparent conductive film, a decorative film, , A transparent substrate, and a member in which these are laminated.

The transparent pressure-sensitive adhesive sheet can be obtained by applying a photo-curable composition for a transparent pressure-sensitive adhesive sheet to a release film and irradiating the applied composition with ultraviolet rays using an ultraviolet irradiation device or the like. The thickness of the transparent pressure sensitive adhesive sheet is usually 5 to 1,000 μm, preferably 10 to 400 μm, more preferably 15 to 300 μm. If the thickness of the transparent pressure sensitive adhesive sheet is 5 mu m or more, the ease of adhering operation is increased. If the thickness is 1000 mu m or less, the control of the film thickness is easy. In the method of forming a transparent pressure-sensitive adhesive sheet of the present invention, a known coating method can be used for coating (coating), and a conventional coater such as a gravure roll coater, a reverse roll coater, , Dip roll coater, bar coater, knife coater, spray coater, comma coater, direct coater and the like can be used.

The surface (pressure-sensitive adhesive surface) of the transparent pressure-sensitive adhesive sheet of the present invention may be protected by a release film (separator) until use. Further, each of the pressure-sensitive adhesive surfaces (both surfaces) of the transparent pressure-sensitive adhesive sheet may be protected by two release films or may be protected in a roll-like form by a single release film on both sides do. The release film is used as a protective material for the transparent pressure sensitive adhesive sheet, and is peeled off when adhered to the adherend. Further, the release film may not necessarily be provided. As the release film, a commonly used release film or the like can be used without particular limitation, and for example, a plastic film surface-treated with a release agent such as a silicone system, a long chain alkyl system or a fluorine system can be used. The release film can be formed by a known method. The thickness and the like of the release film are not particularly limited, and the thickness of the two release films may be the same or different. The peeling film may be of a different kind, and the peelability can be controlled by changing its stiffness.

&Lt; Transparent conductive film laminate &

The transparent pressure sensitive adhesive sheet of the present invention is suitably used as a pressure sensitive adhesive sheet for fixing a transparent conductive film (hereinafter sometimes referred to as a pressure sensitive adhesive sheet for fixing a transparent conductive film). By laminating the pressure-sensitive adhesive sheet for fixing a transparent conductive film to the surface of the conductive layer of the transparent conductive film according to a conventional method, a laminate (transparent conductive film laminate) is formed. This laminate has excellent adhesive strength and less corrosion of the conductive layer and can be suitably used for a touch panel. Further, the pressure-sensitive adhesive sheet for fixing a transparent conductive film of the present invention may have a substrate, or may be a double-sided pressure-sensitive adhesive sheet having no substrate and including only a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer may include a single layer, or a plurality of layers may be laminated. Among these, a double-sided pressure-sensitive adhesive sheet having no base material and containing only a pressure-sensitive adhesive layer is preferable from the standpoint of ensuring transparency and shape-conformability (step difference absorbency).

The transparent conductive film used in the present invention may be any transparent conductive film having a conductive layer on at least one surface layer and a transparent conductive film formed by evaporation or coating of a conductive material on the surface layer of the transparent substrate. Among them, there is an advantage that a transparent conductive film having a conductive layer in which a conductive material is formed by vapor deposition can be easily manufactured. The conductive material to be deposited or coated on the conductive layer of the transparent conductive film is not particularly limited, and specific examples thereof include indium tin oxide, indium oxide, tin oxide, zinc oxide, cadmium oxide, gallium oxide and titanium oxide. Among them, indium tin oxide having excellent transparency and conductivity is particularly suitable.

As the transparent conductive film, a substrate on which a conductive material is deposited or coated is not particularly limited, but glass and resin film can be mentioned. Examples of the resin film include a polyethylene terephthalate film, a polybutylene terephthalate film, a polyethylene naphthalate film, a polyethylene film, a polypropylene film, a cellophane, a diacetylcellulose film, a triacetylcellulose film, an acetylcellulose butyrate film, A vinyl chloride film, a polyvinylidene chloride film, a polyvinyl alcohol film, an ethylene-vinyl acetate copolymer film, a polystyrene film, a polycarbonate film, a polymethylpentene film, a polysulfone film, a polyetheretherketone film, Film, a polyether imide film, a polyimide film, a fluororesin film, a nylon film, an acrylic resin film, a polycycloolefin film and the like. Among them, a polyethylene terephthalate film having excellent transparency and durability is preferable.

The transparency of the transparent conductive film is preferably 80% or more of the total light transmittance, and more preferably 90% or more of the total light transmittance. When the transparency of the transparent conductive film is within the above range, transparency of the display mounted with the touch panel device using the transparent conductive film is easily maintained. The thickness of the transparent conductive film laminate is usually 0.1 mm to 2.0 mm.

It is preferable that the rate of increase of the electric resistance value of the conductive film layer after leaving for 500 hours at 60 DEG C and 90% RH is 20% or less, more preferably 10% or less, particularly 5% or less. As the rate of increase is smaller, the corrosion of the metal forming the transparent conductive film is suppressed, and the performance when the metal is embedded in the touch panel or the like is improved. The rate of increase of the electrical resistance value can be calculated by the following equation (3).

(Initial electrical resistance value) / (initial electrical resistance value) x 100 (3) The rate of increase of the electrical resistance value of the conductive film layer = ((electrical resistance value after leaving for 500 hours at 60 캜, 90% RH) )

The touch panel of the present invention has a transparent conductive film laminate formed by bonding the above-mentioned pressure-sensitive adhesive sheet for fixing a transparent conductive film to a transparent conductive film. The configuration of the touch panel is not particularly limited, and for example, the configuration disclosed in Patent Document 2 can be used. Among them, it is preferable that the touch panel is of a capacitive type.

As a specific construction example, the transparent conductive film laminate having the transparent conductive film-fixing pressure-sensitive adhesive sheet as a double-sided pressure-sensitive adhesive sheet and a transparent conductive film formed on one surface of the transparent conductive film laminate is placed in a two- Type touch panel device can be exemplified. Or at least one of the transparent conductive films having the pressure-sensitive adhesive layer provided in two layers may be the transparent conductive film laminate, and the transparent conductive film having the pressure-sensitive adhesive layer on the side of the image display module may be used as the preferable structure . As another suitable configuration example, the transparent conductive film laminate having the transparent conductive film-fixing adhesive sheet as a double-sided adhesive sheet and the transparent conductive film formed on both surfaces of the double-sided adhesive sheet may be fixed to the display panel And a capacitive touch panel fixed between the image display modules. In this configuration, since the touch panel can be manufactured by fixing the display panel, the transparent conductive film laminate, and the image display module using a fixing tape or a fixing adhesive, the assembling process is facilitated.

The protective panel of the touch panel of the present invention is not particularly limited, and examples thereof include (meth) acrylic resin, polycarbonate resin, glass, and polyethylene terephthalate resin. Among them, a (meth) acrylic resin excellent in transparency and light weight is preferable.

The display panel of the touch panel of the present invention may have a decoration section. Specific decorative portions include, for example, letters and figures visually recognized around the image display portion of the portable electronic terminal, and black or white notional portions formed on the back of these portions. By forming these decorative portions, designability can be given to the portable electronic device.

The thickness excluding the image display module of the touch panel is preferably 0.3 mm to 3.0 mm. Within the above range, it is easy to make the electronic device in which the touch panel is built thin.

When a transparent conductive film having a pressure-sensitive adhesive layer on the side of the image display module is formed as a transparent conductive film laminate in the form of a two-layered transparent conductive film having a pressure-sensitive adhesive layer, the transparent conductive film- The thickness of the pressure-sensitive adhesive sheet for use is preferably 5 to 300 탆, particularly preferably 10 to 200 탆. In the case where the transparent conductive film having the adhesive layer on the side bonded to the display panel is a transparent conductive film laminate, when the decorative part is formed on the display panel, the thickness of the adhesive sheet for fixing the transparent conductive film is 15 to 300 μm More preferably 25 to 200 mu m. Within this range, the double-faced pressure-sensitive adhesive sheet is likely to follow the decorative part of the display panel.

The touch panel of the present invention can be incorporated in various image display devices according to a conventional method. The object image display device is not particularly limited and may be, for example, an LCD display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), or an electronic paper .

[Example]

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

&Lt; Synthesis of polyurethane (A-1) >

A four-necked flask equipped with a thermometer, a stirrer, a dropping funnel, and a condenser tube having a drying tube was charged with isophorone diisocyanate and polypropylene glycol D-2000 having a hydroxy group having a hydroxyl value of 56 mgKOH / g at the end (manufactured by Mitsui Chemicals, 15 mol of the former and 14 mol of the latter), and then the mixture was heated to 60 DEG C and reacted for 4 hours to obtain a polyurethane having isocyanate groups at both terminals. Subsequently, 2 mol of 2-hydroxyethyl acrylate was added to the obtained polyurethane (1), the temperature was raised to 70 占 폚 and the reaction was carried out for 2 hours to obtain a polyurethane (A-1) having an acryloyl group at the terminal thereof . At this time, after confirming that the peak derived from the isocyanate group was lost by IR, the reaction was terminated. The polyurethane (A-1) thus obtained had a weight average molecular weight of 70,000.

&Lt; Synthesis of polyurethane (A-2) >

And the propylene glycol D-2000 (manufactured by Mitsui Chemical Co., Ltd.) having a hydroxy group having a hydroxyl value of 56 mgKOH / g at the terminal thereof was changed to 6 moles of the former and 7 moles of the latter, A polyurethane (A-2) having an acryloyl group at the terminal thereof was obtained in the same manner as in the synthesis of polyurethane (A-1) except that 2-acryloyloxyethyl isocyanate was reacted. The polyurethane (A-2) thus obtained had a weight average molecular weight of 30,000.

&Lt; Synthesis of polyurethane (A-3) >

Except that the charging ratio of polypropylene glycol D-2000 (manufactured by Mitsui Chemical Co., Ltd.) having isophorone diisocyanate and a hydroxy group having a hydroxyl value of 56 mgKOH / g at the end thereof was changed to 4 moles of the former and 3 moles of the latter, In the same manner as in the synthesis of the urethane (A-1), a polyurethane (A-3) having an acryloyl group at the terminal thereof was obtained. The polyurethane (A-3) thus obtained had a weight average molecular weight of 8,000.

&Lt; Weight average molecular weight &

The weight average molecular weight was measured by gel permeation chromatography Shodex GPC-101 (manufactured by Showa Denko K.K.) under the following conditions.

Column: LF-804 (manufactured by Showa Denko K.K.)

Temperature of column: 40 ° C

Sample: 0.2 mass% tetrahydrofuran solution

Flow rate: 1 ml / min

Eluent: tetrahydrofuran

Detector: RI detector

&Lt; Examples 1 to 13 and Comparative Examples 1 to 3 >

(D) other than the components (A) to (C), and the photopolymerization initiator (B), the (meth) acrylic acid ester (E) were blended according to the compositions shown in Table 1 and mixed using a dispenser at room temperature to prepare a uniform photocurable composition for a transparent pressure-sensitive adhesive sheet. The acid value of the obtained composition is as shown in Table 1. The numerical values of the components (A) to (D) in Table 1 are the mass% of the components (A) to (D) (Parts by mass).

Subsequently, the prepared photocurable composition for a transparent pressure-sensitive adhesive sheet was applied to a peelable PET film (100 mm x 100 mm x 75 m) with a thickness of 100 m after curing using an applicator, The film was covered with a film and then irradiated using a UV irradiation device (UV irradiation device 4 kw x 1, output: 160 W / cm, metal halide lamp manufactured by Denki Kikai K.K.) at a distance of 12 cm, a lamp moving speed of 20 m / cm < ² > to obtain a transparent pressure-sensitive adhesive sheet sandwiched between peeling PET films. With respect to this transparent pressure-sensitive adhesive sheet, the rate of increase in the electrical resistance of the ITO film, the adhesive force, and the total light transmittance were evaluated by the method described below. The results are shown in Table 1.

(Rate of increase of electrical resistance of ITO film)

The transparent pressure sensitive adhesive sheet was cut into a size of 50 mm x 50 mm, and then a peelable PET film having a thickness of 50 m was peeled off. A transparent pressure-sensitive adhesive sheet from which a peeled PET film was peeled off was attached to the center of an ITO film of a PET film on which a 100 mm x 100 mm ITO film was deposited to form a laminate.

Using a resistivity meter, Lester GP (manufactured by Mitsubishi Chemical Corporation), the electrical resistance R ₁ between both ends of the ITO film with the transparent pressure-sensitive adhesive sheet adhered thereto was measured. Subsequently, the laminate was allowed to stand under the environment of 60 ° C and 90% RH for 500 hours, and left for 1 hour under the environment of 23 ° C and 50% RH. The electric resistance R ₂ was measured in the same manner as the electric resistance R ₁ did. The electrical resistance increase rate [%] of the ITO film was calculated from the following equation (4).

Increase rate of electric resistance [%] = (R ₂ -R ₁ ) / R ₁ × 100 (4)

The lower the rate of increase of electrical resistance, the more the corrosion of the conductive film is suppressed. A case where the rate of increase in the electrical resistance of the ITO film is less than 5% is evaluated as & cir &, a case where the rate of increase is less than 10% is evaluated as DELTA, and a case where the rate is 10%

(Measurement of Adhesive Force of Adhesive Sheet)

The pressure-sensitive adhesive sheet was cut into a size of 25 mm x 100 mm, and a peelable PET film having a thickness of 50 mu m on one side of the pressure-sensitive adhesive sheet was peeled off and a 50 mu m thick PET film having a corona- (Measuring surface) was attached to a glass plate, and a 2 kg rubber roller (width: about 50 mm) was reciprocated one time to prepare a sample for measurement. The obtained measurement sample was allowed to stand in an environment of 23 ° C and a humidity of 50% for 24 hours, subjected to a tensile test in the 180 ° direction at a peeling rate of 300 mm / min according to JIS Z0237, and the adhesive force / 25 mm) was measured. The obtained measured value was regarded as adhesive force.

(Total light transmittance)

The transparent pressure sensitive adhesive sheet was cut into a size of 30 mm x 30 mm, and then a peelable PET film having a thickness of 50 m was peeled off. The peeled PET film was peeled off from the transparent adhesive sheet, and a 75 占 퐉 peeled PET film was peeled off to obtain a sample for measurement. The total light transmittance of the sample for measurement was measured using a haze, transmittance, and reflectance system HR-100 (manufactured by Murakami Shikisugi Co., Ltd.).

(Refractive index)

The refractive index of the pressure-sensitive adhesive sheet at a wavelength of 589 nm at 20 캜 was determined using a refractive index meter (DR-M2, manufactured by Atago Co., Ltd.).

Claims

(Meth) acrylic acid ester (B) having a hydroxyl group, a (meth) acrylate ester represented by the following formula (1), and a (meth) acryloyl group having a (D) and a photopolymerization initiator (E) other than the components (A) to (C) and having an acid value of 0 to 5 mgKOH / g, and a photopolymerizable monomer Composition.
[Chemical Formula (1)
CH ₂ ═CR ¹ -CO-OR ² - (O) _n -A (1)
(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is an alkylene group having 1 to 6 carbon atoms, A is a group having an aromatic ring, and n is 0 or 1.)

The photocurable composition for a transparent pressure-sensitive adhesive sheet according to claim 1, wherein the polyurethane (A) is a polyurethane having a (meth) acryloyl group bonded to the end of a polyoxyalkylene chain via a urethane bond.

The positive resist composition as claimed in claim 1 or 2, wherein the polyurethane (A) is contained in an amount of 10 to 40 mass%, the hydroxy group-containing (meth) acrylate ester (B) is contained in an amount of 2 to 10 mass% (Meth) acrylic acid ester (C) in an amount of 40 to 70 mass%, 8 to 30 mass% of a polymerizable monomer (D) other than the components (A) to (C) and 100 mass parts of the components (A) Wherein the photopolymerization initiator (E) is contained in an amount of 0.05 to 5 parts by mass based on 100 parts by mass of the photopolymerization initiator.

The photocurable composition for a transparent pressure-sensitive adhesive sheet according to claim 1, wherein A in the formula (1) is a group having one or two aromatic rings.

The photocurable composition for a transparent pressure-sensitive adhesive sheet according to claim 1, wherein the (meth) acrylic acid ester (B) having a hydroxy group is hydroxyalkyl (meth) acrylate and the alkyl moiety has 2 to 10 carbon atoms.

The polyurethane resin composition according to claim 1, wherein the polyurethane (A) is a polyurethane in which an acryloyl group is bonded through a urethane bond to the end of a polyoxyalkylene chain having 3 carbon atoms in the repeating unit,
(Meth) acrylic acid ester (B) having a hydroxy group is hydroxyethyl acrylate,
Wherein the (meth) acrylic acid ester (C) represented by the above formula (1) is at least one selected from the group consisting of m-phenoxybenzyl acrylate, 2- (1-naphthyloxy) ethyl acrylate, 2- , Benzyl acrylate, and the like.
Wherein the polymerizable monomer (D) other than the components (A) to (C) is 2-ethylhexyl acrylate and / or isostearyl acrylate.

The polyurethane resin composition according to claim 6, which comprises 9 to 41% by mass of the polyurethane (A)
1 to 16% by mass of the (meth) acrylic acid ester (B) having a hydroxyl group,
40 to 71 mass% in the case of (meth) acrylic acid ester (C) represented by the above-mentioned formula (1) is m-phenoxybenzyl acrylate, 40 to 71 mass% in the case of 2- (1-naphthyloxy) Phenoxybenzyl acrylate is 40 to 65 mass% when it is 2- (o-phenylphenoxy) ethyl acrylate and 39 to 65 mass% when m-phenoxybenzyl acrylate and benzyl acrylate are contained, To 70 mass% and benzyl acrylate in an amount of 1.0 to 10 mass%
, 8 to 28% by mass of the polymerizable monomer (D) other than the components (A) to (C)
, And 0.5 to 3 parts by mass of a photopolymerization initiator (E) based on 100 parts by mass of the components (A) to (D).

The photocurable composition for a transparent pressure-sensitive adhesive sheet according to claim 1, which gives a cured product having a refractive index of 1.50 to 1.60.

A transparent pressure-sensitive adhesive sheet having a refractive index of 1.50 to 1.60 obtained by curing the photocurable composition for a transparent pressure-sensitive adhesive sheet according to claim 1.

A pressure-sensitive adhesive sheet for fixing a transparent conductive film, wherein the transparent pressure-sensitive adhesive sheet according to claim 9 is used for bonding a transparent conductive film.

11. The transparent conductive film laminate according to claim 10, wherein the pressure-sensitive adhesive sheet for fixing a transparent conductive film is adhered to the surface of the conductive layer of the transparent conductive film.

A touch panel having the transparent conductive film laminate according to claim 11.

An image display apparatus comprising the touch panel according to claim 12.